Device and methods for processing blood in extracorporeal circulation

ABSTRACT

A device for treating blood in an extracorporeal blood circuit, the device including a centrifugal pump provided with a transparent enclosure that is connected, by means of an inlet duct, to the outlet of a venous reservoir, the venous reservoir having an inlet that is connected to receive blood from a patient. The transparent enclosure of the pump is connected monolithically to the base of a structure that comprises a heat exchanger and an oxygenator. The structure also supports monolithically, at the peripheral region, an arterial filter that receives the blood in output from the oxygenator and is provided with a connector for coupling to an arterial line for return of the blood to the patient.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation of U.S. Ser. No. 10/805,165, filedMar. 18, 2004, the contents of which are hereby incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to a method and device for processing blood inextracorporeal circulation. Reference is made to co-pending applicationU.S. Ser. No. 10/804,583, filed on Mar. 18, 2004, and entitled “Deviceand Methods for Processing Blood in Extracorporeal Circulation” which isassigned to the assignee of the present invention and which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

During certain surgical procedures it is necessary to establish acircuit for extracorporeal circulation of the blood of the patient. Suchcircuits may comprise devices such as blood reservoirs which may includea venous reservoir, that is meant to collect the blood that leaves thepatient, and a cardiotomy reservoir for containing the blood drawn byrecovery from the operating field, a pump for conveying blood in thecircuit, a heat exchanger in which the blood encounters a heat exchangesurface that maintains blood temperature at a desired value, anoxygenation device that is meant to transfer oxygen to the blood, andfinally a filter known as an arterial filter, that is connected in thearterial line and is meant to retain any air bubbles that are present inthe blood before the blood is returned to the patient.

All these devices can be present in the extracorporeal circuit asseparate elements or they can be integrated in various combinations suchas disclosed in co-pending U.S. patent application Ser. No. 09/920,999filed Aug. 2, 2001 (U.S. Published Application No. 2002/0049401) whichis assigned to the assignee of the present invention, and which isincorporated herein by reference in its entirety.

A need in this field exists, however, for a monolithic structure whichintegrates into a single package all of the various components necessaryfor use in an extracorporeal blood circuit used during heart bypasssurgery or as an assist circuit during beating heart surgery.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a device that ensuresoptimum conditions of removal of the air contained in the device duringpriming and use and which is configured to allow an operator of thedevice to maintain visual contact with critical portions of the deviceduring use so that the operator can take corrective action when aproblem situation is observed.

This object and other objects that will become better apparenthereinafter are achieved by a device for treating blood inextracorporeal circulation that comprises an integrated structure thatincludes a venous reservoir, a cardiotomy reservoir, a centrifugal bloodpump, an oxygenator, a heat exchanger and an arterial blood filter, allof which are inter connected by means of various tubing lines and/orducts. The integrated structure forms a complete system which includesall of the components required in an extracorporeal blood circuit usedduring heart bypass surgery or used to assist the heart during beatingheart surgery. The integrated structure is configured to be shipped to auser as a completely assembled and interconnected system oralternatively, to more efficiently use packaging space some minimalassembly might be required by the user.

The integrated structure includes a centrifugal pump provided with atransparent enclosure that is connected, by means of an inlet duct, tothe outlet of the venous reservoir. The inlet of the venous reservoir isconnected to a venous line for conveying the blood from a patient. Thetransparent enclosure of the centrifugal pump is connected to theportion of the unitary structure that comprises the heat exchanger andoxygenator. The centrifugal pump may be a standard component whichconnects to the structure in a manner known in the art. Usually thecentrifugal pump will be connected prior to packaging so that it isshipped and is received by the user as part of the monolithic structurealthough it could be shipped unconnected from the structure andconnected by the user after receipt. That portion of the unitarystructure comprising the oxygenator/heat exchanger has an inletconnected to receive blood from the centrifugal blood pump and alsosupports monolithically, at a peripheral region, the arterial filter.The arterial filter has an inlet connected to receive blood from anoutlet of the oxygenator/heat exchanger. The arterial filter has anoutlet connected to an arterial line for return of the blood to thepatient.

In one embodiment the invention comprises an integrated device foroxygenating and filtering blood flowing through an extracorporeal bloodcircuit. The integrated device comprises a blood reservoir having aninlet for receiving venous blood and an outlet for supplying venousblood. The device includes a blood pump having an inlet connected toreceive blood from the outlet of the blood reservoir and an outletconnected to a blood inlet of a heat exchanger. The heat exchanger has ablood outlet for supplying temperature controlled venous blood to theinlet of an oxygenator. The oxygenator has an outlet for supplyingoxygenated blood to the inlet of an arterial blood filter. The arterialblood filter has an outlet adapted for connection to an arterial linefor return of oxygenated blood to the patient. The integrated deviceincludes a monolithic housing having a first portion for defining theblood reservoir, a second portion for defining the blood pump, a thirdportion for defining the heat exchanger, a fourth portion for definingthe oxygenator and a fifth portion for defining the arterial bloodfilter.

The blood pump may comprise a centrifugal pump that is positioned withinthe monolithic housing such that an axis of the centrifugal pump ishorizontal. The blood reservoir may comprise a combined venous reservoirand cardiotomy reservoir. Further, the monolithic housing of theintegrated device may comprise connection means which allows removableconnection of the first portion or the second portion of the housing.

In another embodiment the invention comprises a system for establishingan extracorporeal blood circuit. The system includes a blood reservoir,a blood pump, a heat exchanger, an oxygenator, an arterial blood filterand a housing for incorporating and interconnecting the blood reservoir,the blood pump, the heat exchanger, the oxygenator, and the arterialblood filter into a monolithic structure. The housing has an inlet forreceiving venous blood from a patient and supplying the venous blood tothe blood reservoir and an outlet for supplying oxygenated blood fromthe arterial blood filter to a patient.

The blood pump may comprise a centrifugal pump which is positionedwithin the housing such that an axis of the pump is horizontal. Theblood reservoir may comprise a combined venous reservoir and cardiotomyreservoir. Further, the housing may comprise connection means forallowing removable connection of the blood reservoir or the centrifugalblood pump.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages will become better apparent fromthe description of two embodiments of the invention, illustrated by wayof nonlimiting example in the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the invention.

FIG. 2 is another longitudinal sectional view of the invention accordingto a different embodiment of the venous reservoir.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, the reference numeral 1 generally designatesthe device according to the invention, which comprises variouscomponents which have been integrated into a unitary or monolithicstructure. These components are interconnected by various tubing linesor ducts to establish a blood flow path through the unitary structureaccording to the arrows shown in the figures and which will be describedin detail, hereafter.

The unitary structure includes a venous reservoir 2, which is providedwith an input connector 2 a for connection to a venous line forreceiving blood from the patient. Blood received from the patientthrough connector 2 a passes through a filter 2 b before it reachesvenous reservoir 2. A cardiotomy reservoir 2 c is contained withinvenous reservoir 2 and is connected receive blood recovered from theoperating field through an inlet connector 2 d. Blood received throughinlet connector 2 d passes through a filter 2 e before it reaches venousreservoir 2.

An outlet connector 2 f of venous reservoir 2 is connected at one end ofduct 3. The other end of duct 3 is connected to an inlet of centrifugalpump 4. Centrifugal pump 4 has a transparent enclosure which defines anoutlet connector 4 b which is connected to delivery duct 4 a, connectedto provide blood from centrifugal pump 4 to an inlet connector 5 a ofheat exchanger 5. Heat exchanger 5 is provided with an outlet connector5 b that is configured to convey the blood to inlet 6 a of oxygenator 6.

From the outlet 6 b of the oxygenator 6, the blood reaches arterialfilter 7, which is provided with an outlet connector 7 a for connectionto an arterial line for the return of the blood to the patient.

The transparent enclosure of the centrifugal pump 4 is connectedmonolithically to the end face of the structure that comprises the heatexchanger 5 and the oxygenator 6. Centrifugal pump 4 is oriented so thatthe pump axis is horizontal and outlet connector 4 b is positioned atthe top of the pump. This arrangement is beneficial for several reasons.First, it essentially ensures the complete removal of any air containedin the pump during its filling since any air bubbles in the device willrise because of their buoyancy and be expelled through the outletconnector at the top of the pump. Second, since the axis of thecentrifugal pump is horizontal the entire rotor and pump chamber arevisible to the operator through the transparent enclosure. This allowsthe operator to visually locate any air bubbles which may pass into orthrough the pump and to take appropriate corrective action in responsethereto.

Furthermore, the ease with which the device may be set up and itsoperating convenience are both enhanced by the fact that the venousreservoir 2 is removably connected to a pedestal 8 that protrudes fromthat portion of the unitary structure that comprises the heat exchangerand the oxygenator by virtue of snap-acting means. This allows thevenous reservoir/cardioplegia reservoir to be constructed as a firstmodule of the system and the oxygenator/heat exchanger/arterialfilter/pump to be constructed as a second module of the system. Thesetwo modules can be detached during shipment to conserve package spaceand assembled by the user by snap fitting the modules together duringset up. Alternatively, they can be shipped completely assembled.

The embodiment shown in FIG. 2 differs from the one described above onlyin that rigid or hard shell venous reservoir 2 is replaced by a flexiblebag 9. Bag 9 is connected to a support 10 that extends from thestructure that comprises the heat exchanger and the oxygenator and isprovided with an inlet connector 9 a for connection to a venous bloodinlet line and with an outlet connector 9 b that is connected to theinlet of pump 4 through duct 3.

The device of the present invention may be used as a fast, efficient andconvenient alternative to the use of various individual components in atraditional extracorporeal blood circuit. Since the structure of thedevice incorporates these various individual components into apreconnected monolithic structure it can be set up and ready for usevery quickly. Further, the present invention is advantageous for use inbeating heart surgery for several reasons. First, since part of theblood is diverted into an extracorporeal circuit the heart has lessblood to pump and therefore beats less making it easier for the surgeonto work on the heart. Second, in cases where it is necessary to changeto full bypass during the surgery the monolithic device of the presentinvention includes an oxygenator and other components which provide thecapacity and function necessary to accommodate the change. The presentinvention also includes methods of using the device to process bloodduring heart bypass or beating heart surgery.

It should be understood that the embodiments disclosed herein representpresently preferred embodiments of the invention. Various modificationsand additions may be made to these embodiments without departing fromthe spirit and scope of the invention.

1. An integrated device for oxygenating and filtering blood flowingthrough an extracorporeal blood circuit comprising: a blood reservoirhaving an inlet for receiving venous blood and an outlet for supplyingvenous blood; a blood pump having an inlet connected to receive bloodfrom the outlet of the blood reservoir and an outlet; a heat exchangerhaving a blood inlet connected to receive venous blood from the outletof the pump and a blood outlet for supplying temperature controlledvenous blood; an oxygenator having an inlet connected to receive venousblood from the outlet of the heat exchanger and an outlet for supplyingoxygenated blood; an arterial blood filter having an inlet connected toreceive oxygenated blood from the outlet of the oxygenator and an outletfor supplying filtered oxygenated blood; and a monolithic housingincluding a first portion for defining the blood reservoir, a secondportion for defining the blood pump, a third portion for defining theheat exchanger, a fourth portion for defining the oxygenator and a fifthportion for defining the arterial blood filter, the second portion beingconfigured such that the outlet of the blood pump is located at a top ofthe second portion of the monolithic housing.
 2. The integrated deviceof claim 1 wherein the blood pump comprises a centrifugal pump.
 3. Theintegrated device of claim 2 wherein the centrifugal pump has an axisand wherein the centrifugal pump is positioned within the monolithichousing such that the axis of the centrifugal pump is horizontal.
 4. Theintegrated device of claim 1 wherein the blood reservoir comprises avenous reservoir and a cardiotomy reservoir.
 5. The integrated device ofclaim 4 wherein the monolithic housing comprises connection means forallowing removable connection of the first portion.
 6. A system forestablishing an extracorporeal blood circuit comprising: a bloodreservoir; a blood pump; a heat exchanger; an oxygenator; an arterialblood filter; and a housing for incorporating and interconnecting theblood reservoir, the blood pump, the heat exchanger, the oxygenator andthe arterial blood filter into a monolithic structure, the housinghaving an inlet for supplying venous blood to the blood reservoir and anoutlet for supplying oxygenated blood from the arterial blood filter,the housing further having a portion which defines the blood pumpincluding a blood pump inlet and a blood pump outlet, the outlet of theblood pump being located at a top of the portion.
 7. The system of claim6 wherein the blood pump comprises a centrifugal pump.
 8. The system ofclaim 7 wherein the centrifugal pump has an axis and wherein thecentrifugal pump is positioned within the housing such that the axis ofthe centrifugal pump is horizontal.
 9. The system of claim 6 wherein theblood reservoir comprises a venous reservoir and a cardiotomy reservoir.10. The integrated device of claim 9 wherein the housing comprisesconnection means for allowing removable connection of the bloodreservoir.